Injection molded components are typically molded in a mold cavity formed between a first mold tool and a second mold tool. The first mold tool is sometimes referred to as the cavity side mold tool and the second mold tool is sometimes referred to as the core side mold tool. Plastic is melted in the mold cavity, and must be sufficiently cooled prior to separating the mold tools and ejecting the molded component. Cooling of the molded component is accomplished via a coolant, such as water, flowing through coolant lines drilled in the first and second mold tools. The mold tools are generally a relatively hard tool steel. Accordingly, the drilled passages are generally drilled as a series of straight segments. If the molded component has a complex or curved outer surface, the straight passages will not be an equal distance from the component as the cooling passages traverse the tool, resulting in uneven cooling of different portions of the tool surface. Cycle time for molding the component is thus dependent on those portions of the tool surface furthest from the cooling passages, and is increased until required cooling is achieved.
One known process, referred to as direct metal laser sintering, provides conformal cooling channels that can be equally spaced from the tool surface to enable more even cooling. The conformal cooling channels are provided by locally melting metal powder with a focused beam, layer by layer. This process is expensive as it is relatively slow and requires unique equipment and training that most mold makers do not have.
Additionally, the layout of the cooling channels is generally performed according to a trial and error, iterative process that relies on the skill level of the tool designer for each iterative layout of the cooling channels. Specifically, the designer selects an initial cooling channel pattern and inputs the layout into a computer that implements a tool design program that indicates the resulting tool surface temperature distribution. If the temperature distribution is not satisfactory, the designer reconfigures the cooling channel layout based on an educated guess, inputs the revised cooling channel layout into the computer, and the tool design program then determines whether the temperature distribution is sufficiently improved. This process is repeated however many times as necessary, is time consuming, and consistently obtaining a satisfactory final result is somewhat uncertain, as this is generally dependent upon the skill of the designer.